JP2001324291A - Heat exchanger and method of manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a brazing area from decreasing due to variation in the clearance of bonding face. SOLUTION: As shown on Fig. 4(b), the bonding face of both tubes 221, 222 is divided into a plurality of sections by making a groove space G which is not bonded to the bonding face. Since the bonding face is divided into a plurality of sections by the groove space G which is not bonded thereto, variation in the clearance of the bonding face is divided among the plurality of sections and decreased even when two flat tubes 221, 222 are bonded over the entire region in the longitudinal direction. Even if molten brazing material is shifted to a part of small clearance and a part of large clearance is not brazed to generate a void, it is confined within a small part of each section and a uniformly brazed state is obtained as a whole, thus ensuring a brazed area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for exchanging heat between fluids flowing through tubes by brazing two types of tubes formed of different materials and a method of manufacturing the same. It is about.

[0002]

2. Description of the Related Art In Japanese Patent Application Laid-Open No. Hei 5-196377, two flat tubes having a plurality of fluid passages therein are thermally joined to each other by means such as brazing or soldering over the entire area in the longitudinal direction. Thus, a heat exchanger has been proposed that transfers heat from a fluid (for example, a refrigerant) flowing in a plurality of fluid passages of one flat tube to a fluid (for example, water) flowing in a plurality of fluid passages of the other flat tube. ing.

[0003]

However, if two flat tubes are joined over the entire area in the longitudinal direction as described in the above-mentioned publication, the clearance of the joining surface varies, and the brazing material melted by the capillary phenomenon causes clearance. Leans towards a small part of. For this reason, a large portion of the clearance becomes a large void as a portion that is not brazed, and the heat conductivity from one tube to the other tube is reduced, and the heat exchange capability is reduced.

In order to increase the heat exchange capability, internal partitions are alternately provided at a plurality of locations in one flat tube to meander a fluid (eg, water) flow passage several times inside. When the clearance of the joint surface also varies in the partition portion, a large portion of the clearance becomes an unbrazed portion and an internal leak occurs. As a result, the fluid is short-circuited in the flow passage, flows therethrough, and passes before the heat is sufficiently exchanged, so that the heat exchange ability is reduced.

The present invention has been made in view of the above-mentioned conventional problems, and is intended to prevent a reduction in brazing area due to a variation in clearance of a joining surface and to effectively suppress a decrease in heat exchange capacity. It is an object of the present invention to provide a heat exchanger and a method for manufacturing the same.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, the first fluid through which the first fluid flows is provided.
While the tube (221) and the second fluid circulate,
A first tube (221) and a second tube (222) formed of a different material;
The two tubes (221, 222) are joined by brazing in a state where their longitudinal directions are aligned.
Of both tubes (221, 22)
A feature is that a groove space (G) where 2) is not bonded is provided, and the bonding surface is divided into a plurality.

Thus, even if two flat tubes are joined over the entire area in the longitudinal direction, the joint surface is divided into a plurality of parts by the above-mentioned groove space (G) where the joint is not made, so that the unevenness of the clearance of the joint surface Also becomes smaller for each of the divided joining surfaces. As a result, even if the molten brazing material becomes a void where the large clearance is not brazed due to approaching the small clearance, it will fit in the small part in the divided joint surface, so the whole brazing state is almost uniform And the brazing area is secured.

According to the second aspect of the invention, the first tube (221) is formed by bonding two plate members (221b, 221c) to form a flow passage for the first fluid, and the bonded portion (P) ) To form a non-joining groove space (G).

The first tube has a plurality of bonded portions serving as internal partitions in the middle of the tube in order to meander the passage of the first fluid a plurality of times. Since these bonded portions do not become heat exchange portions with the second tube, the above-mentioned portions are used to form the above-described groove space (G) that is not joined, so that the joining surface can be reduced without substantially reducing the heat exchange area. Can be formed.

According to the third aspect of the present invention, in the bonding portion (P), the both plate members (22) are formed at an angle (θ) with respect to the entire bonding plane of the two plate members (221b, 221c).
1b, 221c) is characterized by forming a wall portion (H) with which it comes into contact.

[0011] This is to solve the problem that, if the clearance of the bonded portion serving as the internal partition varies, a portion having a large clearance becomes a portion not to be brazed and an internal leak occurs. By creating a portion that rubs on the wall surface that stands up to the entire bonding plane instead of abutting on a flat surface, even if a gap occurs between both plate materials, there is no large clearance at the bonding portion.

As a result, the bonding portion is in a substantially uniform brazing state, the brazing area is secured, and the occurrence of internal leakage can be prevented.

According to the fourth aspect of the present invention, the first tube (221) through which the first fluid flows and the second tube through which the second fluid flows and are formed of a material different from the first tube (221). (222), a method of manufacturing a heat exchanger in which both tubes (221, 222) are joined by brazing in a state where the longitudinal directions of both tubes are matched, and the first tube (221) is provided. Means two plates (221
b, 221c), the bonded portion (P) is pressurized and brazed in a state of being plastically deformed until an uneven shape is formed on the bonded portion (P). (221, 222) is brazed.

In this method, after the first tube is temporarily assembled, the bonded portion is pressed by a press or the like to form an uneven shape to form the above-mentioned standing wall surface. As a result, the variation in the clearance of the joint surface is suppressed, and the close contact is maintained by deforming the two plate materials together.Even if a gap is opened at the time of brazing, a large clearance is provided by the above-mentioned standing wall portion. Not be.

[0015] Thus, the bonding portion is in a substantially uniform brazing state, the brazing area is secured, and the occurrence of internal leak can be prevented.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0017]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) In this embodiment, a heat exchanger according to the present invention is applied to a domestic water heater.
FIG. 1 is an external view of a water heater 100, and FIG.
FIG. In FIG. 2, 200 (enclosed by a two-dot chain line) heats hot water to a high temperature (about 8 in this embodiment).
This is a supercritical heat pump cycle (hereinafter abbreviated as a heat pump) that generates hot water of 5 ° C.).

The supercritical heat pump cycle is
A heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant, for example, a heat pump cycle using carbon dioxide, ethylene, ethane, nitrogen oxide, or the like as a refrigerant.

Reference numeral 300 denotes a plurality of heat retention tanks for keeping the hot water heated by the heat pump 200 in a warm storage state. Each of the heat retention tanks 300 is arranged in parallel with the flow of the hot water (hot water). ing.

In FIG. 2, reference numeral 210 denotes a compressor for sucking and compressing a refrigerant (carbon dioxide in this embodiment).
Reference numeral 10 denotes an electric compressor in which a compression mechanism (not shown) for sucking and compressing the refrigerant and an electric motor (not shown) for driving the compression mechanism are integrated.

Reference numeral 220 denotes a water heat exchanger (radiator) to which the heat exchanger according to the present embodiment is applied, which exchanges heat between the refrigerant discharged from the compressor 210 and hot water. As shown in FIG. 3, the water heat exchanger 220 includes a first tube 221 through which hot water (water) flows and a plurality of second tubes 221 through which a refrigerant flows.
This is a counter-flow type heat exchanger configured so that the flow of the refrigerant and the flow of hot water are brought into contact with each other by bringing the tubes 222 into contact with each other.

Reference numeral 223 denotes a pipe for supplying hot water to the first tube 221;
1 is a pipe for collecting hot water flowing out of
Is a first header tank that distributes and supplies the refrigerant to the plurality of second tubes 222, and 226 is a second header tank that collects and collects the refrigerant flowing out of the plurality of second tubes 222.

The first tube 221 and the second tube 222
Is formed in a flat shape as shown in FIG. The first tube 221 is formed by sandwiching the copper inner corrugated inner fin 221a between a copper plate 221b and a plate 221c in which one surface of a copper plate is coated (cladded) with stainless steel.
b and 221c are brazed.

The second tube 222 is made of aluminum and is formed by extrusion or drawing. By the way, both tubes 221 and 222 are
They are brazed so that their longitudinal directions coincide with each other.

By the way, in FIG. 2, 230 is the water heat exchanger 2
Reference numeral 240 denotes an electric expansion valve (decompressor) for reducing the pressure of the refrigerant flowing out of the refrigerant 20. An evaporator that absorbs the refrigerant and discharges the refrigerant toward an accumulator 250 (a suction side of the compressor 210) described later.

The reference numeral 250 designates a compressor which separates the refrigerant flowing out of the evaporator 240 into a gas-phase refrigerant and a liquid-phase refrigerant and
10 and the heat pump 200
It is an accumulator that stores excess refrigerant inside.

Reference numeral 260 denotes a blower (blowing air amount adjusting means) which blows air (outside air) to the evaporator 240 and can adjust the blowing amount. The blower 260, the compressor 210 and the expansion valve 230 are described later. Is controlled by an electronic control unit (ECU) 270 based on the detection signals of the respective sensors.

Reference numeral 271 denotes a refrigerant temperature sensor (refrigerant temperature detecting means) for detecting the temperature of the refrigerant flowing out of the water heat exchanger 220, and 272 detects the temperature of hot water flowing into the water heat exchanger 220. It is a first hot water temperature sensor (first hot water temperature detecting means).

Reference numeral 273 denotes a refrigerant pressure sensor (refrigerant pressure detecting means) for detecting the pressure of the refrigerant flowing out of the water heat exchanger 220 (the refrigerant pressure on the high pressure side).
It is a second hot water temperature sensor (second hot water temperature detecting means) for detecting the temperature of hot water flowing out of the water heater 20. The detection signals of the sensors 271 to 274 are input to the ECU 270.

Here, the refrigerant pressure on the high pressure side refers to the compressor 2
10 refers to the pressure of the refrigerant present in the refrigerant passage from the discharge side of the expansion valve 230 to the inflow side of the expansion valve 230.
It is substantially equal to 0 discharge pressure (the internal pressure of the water heat exchanger 220). On the other hand, the refrigerant pressure on the low pressure side refers to the pressure of the refrigerant present in the refrigerant passage from the outlet side of the expansion valve 230 to the suction side of the compressor 210, and the pressure is the suction pressure of the compressor 210 (evaporator 240 Internal pressure).

Reference numeral 400 denotes an electric water pump (hereinafter, abbreviated as a pump) for supplying (circulating) hot water to the water heat exchanger 220 and adjusting the amount of hot water. This is a shut-off valve for preventing tap water supplied from a not-shown) from flowing into the water heat exchanger 220. The pump 400 and the shut-off valve 410 are also EC
It is controlled by U270.

Next, the water heat exchanger 220 according to this embodiment
An outline of the manufacturing method of the present invention will be described.

First, the inner fin 22 is placed on the plate 221b.
1a and the pipes 223, 224 are set, and the plate material 221c is set.
And the nail provided on the edge of the plate member 221b is bent and caulked to assemble the first tube 221 (temporary assembling step). At this time, both sides of the inner fin 221a and the plate 2
A brazing material is applied to the bonding surfaces of 21b and 221c.

This is sandwiched between two jigs, heated for a predetermined time in a furnace while applying a load, and they are integrally joined by brazing (phosphor copper brazing step).

Next, the first tube 221 brazed
Above the second tube 222 and the header tanks 225 and 22
After temporarily assembling the parts such as 6 sequentially, these parts are temporarily fixed by a temporary fixing jig such as a wire (temporary assembling step).

Next, the components assembled in the temporary assembling process are heated in a furnace for a predetermined time, and they are integrally joined by brazing (aluminocolo brazing process). In this embodiment, A4343 is adopted as the brazing material, and the brazing material is applied to the outer wall of the tube material by means such as coating (cladding), coating, or thermal spraying.

Next, the features of this embodiment will be described.

FIG. 4A shows the water heat exchanger 22 at the beginning of the trial production.
0 is a cross-sectional view of the tube, and (b) is a cross-sectional view of the tube of the water heat exchanger 220 according to the first embodiment of the present invention.

In the present invention, the joint surface between the tubes 221 and 222 is provided with a groove space G that is not joined, and the joint surface is divided into a plurality of sections. Thereby, two flat tubes 2
Even if the joints 21 and 222 are joined over the entire area in the longitudinal direction, the joint surface is divided into a plurality of parts by the above-mentioned groove space G that is not joined. Become smaller.

As a result, even if the molten brazing material becomes a void in which the large clearance portion is not brazed due to the small clearance portion, the molten brazing material can be accommodated in the small portion in each of the divided joining surfaces, and thus the whole is substantially uniform. The brazing state is obtained, and the brazing area is secured.

The groove space G that is not joined is formed by using the bonded portion P of the two plate members 221b and 221c of the first tube 221. This is the first tube 22
In the tube 1, a plurality of bonded portions P serving as internal partitions are provided in the middle of the tube in order to meander the fluid flow passage a plurality of times. This bonded portion P is the second tube 22
Since this portion does not become a heat exchange portion with No. 2, by using this portion to form the above-mentioned groove space G not to be joined, the separation groove of the joining surface is formed without substantially reducing the heat exchange area.

(Second Embodiment) FIG. 5A is a sectional view of the first tube 221 before pressing, and FIG.
It is sectional drawing of the 1st tube 221 after the press in embodiment.

In the present invention, the two plate members 221b, 221b, 221b, 221b, and 221b are arranged within the bonded portion P of the first tube 221 at an angle θ with respect to the entire bonding plane of the two plate members 221b and 221c.
221c forms a wall portion H with which it contacts.

This is to solve the problem that, if the clearance of the bonded portion P serving as the internal partition varies, a portion having a large clearance becomes a portion not to be brazed and an internal leak occurs. Is not a simple flat surface but a portion that slides on a wall surface H that stands up to the entire bonding plane to create a large clearance at the bonded portion P even if a gap occurs in both plate members 221b and 221c. Does not.

As a result, the bonded portion P is in a substantially uniform brazing state, the brazing area is secured, and the occurrence of internal leakage can be prevented.

Further, the manufacturing method of the shape is such that when the two plate members 221b and 221c forming the first tube 221 are bonded, the bonded portion P is pressurized and the flat portion which is the bonded portion P is pressed. Brazing is performed after plastic deformation until an uneven shape is formed.

In this method, after the first tube 221 is temporarily assembled, the bonded portion P is pressed by a press or the like to form an uneven shape in order to form the above-mentioned standing wall surface H.
For this purpose, for example, a brazing jig may be used like a press mold to form the bonded portion P under pressure, and then brazing may be performed while the tube and the jig are kept in close contact with each other.

As a result, the variation in the clearance between the joining surfaces can be suppressed, and the two plates 221b and 221c are deformed together to maintain the close contact state. There is no large clearance due to the wall.

As a result, the bonded portion P is in a substantially uniform brazing state, the brazing area is secured, and the occurrence of internal leakage can be prevented.

(Other Embodiments) In the above embodiment, the present invention is applied to a water heat exchanger for exchanging heat between a refrigerant and hot water, but the heat exchanger according to the present invention is not limited to this. The present invention can also be applied to other heat exchangers such as a radiator for exchanging heat between water and air, a radiator for exchanging heat between refrigerant and air, and a gas cooler.

In the above embodiment, the bonding portion P
Although the uneven shape formed in the above was substantially semicircular, the present invention is not limited to this, and other shapes such as a square shape may be used.

[Brief description of the drawings]

FIG. 1 is an external view of a water heater according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a water heater according to one embodiment of the present invention.

FIG. 3A is a side view of a water heat exchanger according to an embodiment of the present invention, and FIG. 3B is a front view.

4A is a cross-sectional view of a tube of a water heat exchanger at the beginning of a trial production, and FIG. 4B is a cross-sectional view of a tube of the water heat exchanger according to the first embodiment of the present invention.

FIG. 5A is a cross-sectional view of a first tube before pressing,
(B) is the first after pressing in the second embodiment of the present invention.
It is sectional drawing of a tube.

[Explanation of symbols]

 221 First tube 221b Plate (plate material) 221c Plate (plate material) 222 Second tube G Groove space not to be joined H Wall surface portion standing at angle θ P Plate bonding portion θ Angle to bonding plane

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Norihide Kawaji 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation (72) Inventor Tsuyoshi Okinoya 1-1-1, Showa-cho, Kariya-shi, Aichi Inside Denso Co., Ltd. (72) Inventor Ken Yamamoto 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Co., Ltd. (72) Tomoaki Kobayakawa 1-1-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Kazutoshi Kusakari 1-1-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Michiyuki Saikawa 2-6-1 Nagasaka, Yokosuka City, Kanagawa Prefecture Yokosuka Research, Central Electricity Research Institute In-house F term (reference) 3L065 CA17 3L103 AA01 AA36 DD10 DD53

Claims (4)

[Claims] A first tube (22) through which a first fluid flows.
1) and a second tube (222) formed of a different material from the first tube (221), through which the second fluid flows.
2) The two tubes (221, 222) are joined by brazing in a state where the longitudinal directions of the two tubes are made to coincide with each other. A heat exchanger, wherein a groove space (G) that is not joined is provided, and the joining surface is divided into a plurality of sections. 2. The first tube (221) is formed by bonding two plate members (221b, 221c) to form a flow passage for a first fluid, and using the bonded portion (P). The heat exchanger according to claim 1, wherein a groove space (G) that is not joined is formed. 3. The both plate members (221b, 221c) have an angle (θ) with respect to the entire bonding plane of the both plate members (221b, 221c) in the bonded portion (P).
The heat exchanger according to claim 1 or 2, wherein a wall portion (H) with which 1c) contacts is formed. 4. A first tube (22) through which a first fluid flows.
1) and a second tube (222) formed of a different material from the first tube (221), through which the second fluid flows.
2) is a method for manufacturing a heat exchanger which is joined by brazing in a state where the longitudinal directions thereof are made to coincide with each other, wherein the first tube (221) comprises two plate members (221).
b, 221c), the bonding portion (P) is pressurized and brazed in a state of being plastically deformed until an uneven shape is formed on the bonding portion (P). (221, 222) is brazed, The manufacturing method of the heat exchanger characterized by the above-mentioned.